Clutch mechanism



P c. G.ISTRANDLUND 2,358,261

CLUTCH MECHANISM Filed June 17. 1940 3 Sheets-Shet 1 INVENTOR: Carl(iStr-nd Sept. 12, 1944. c STRANDLUND 2,358,261

CLUTCH MECHANISM Filed June 17, 1940 3 Sheets-Sheet 2 VIII/III,

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\ I INV ENTOR:

- Carl 6 straw Zund p 4- c. e. STRANDLUND 5 CLUTCH MECHANISM Filed June17, 1940 3 Sheets-Sheet 3 I N VEN TOR:

IO U w 8 8 C l atra. dund 'Patentecl Sept. 12, 1944' a CLUTCH MEcnANisMv e g Carl G. Strandlund, Moline, Ill., assignor ,to Deere & Company,nois Application June 17, 1940, Serial No. 340,925

14 Claims.

7 The present invention relates generally to agricultural implements andmore particularly to power lift clutches by which a constantly rotatablepart is operatively connected ,With an intermittently driven part foreffecting some adjustment of the implement, such as-raising-or loweringthe tool or toolsinto and out of the ground. Clutch mechanism of thisgeneral type Moline, 111., a corporation of Illi- 7 is disclosed in myprior Patents Nos. 2,119,757 and 2,156,362, issued June '7, 1938, andMay 2, 1939, respectively. t

Theobject and general. nature of this invention is the provision of aself-interrupting clutch for agricultural uses which has its operatingparts, or at least the major portions thereof, enclosed I in a lubricanttightcasing or housing, which not only keeps .the operating partsadequately lubricated but completely seals such parts from dirt, dustand the like, thereby providing a smoother operating and longer livedclutch mechanism. A .clutch mechanism of this type is particularlyadapted for use in territories which are dusty and 1 Where the soil isof an abrasive nature.

A further feature of this invention is the provision of clutch mechanismthat is especially compact and hencerequire s little space on theimplement. As a result, there is adequate clear ance between the clutchmechanism'and the ground and all associated operating parts. .It

will be recognized that this is an important feae ture, especially wherethe clutch mechanism itself is to be enclosed. Certain prior clutchmechanisms with which I am familiar arefairly bulky, due at least inpart to the fact that the connecting means between the driving anddriven members extends generally radially from one to the other. ;Sinceeach of the driving and driven members,

must be large enough to have adequate strength to sustain all the forcesto which it is subjected, it will be seen that if clutch mechanism ofthis character, where the connecting part extends generally radiallyfrom one member to the other, is provided with an enclosing casing itwould have to be quite large and might require more space on theimplement, in order to obtain the necessary clearance between the groundand asmechanism;

, sociated operating parts, than could be provided in a practicalcommercial machine. According to the present invention, the connectingmeans between the driving and driven parts of the clutch is arranged,not ,to extend radially outwardly but, rather, in close'overlappingrelation so that the radial dimension of the clutch is smalland can, as a practicalproposition, be enclosed in a casing thatisquitesmall and does not reduce the clearance to any objectionableextent.

Another important feature of the present invention resides in theprovision of aclutch of the Y self-interrupting type in which a drivingpart is connected with a driven part through a roller supporting-strapin which the latter transmits the driving force in tension, rather thanin com- .pression, or a pushing strain, as in former clutches. Thisparticular feature materially contributes to the compactness of my novelclutch mechanism. Also, in this connection it is a further feature ofthis invention to provide the drivingmember with external notches orscallops} whereby this member,'which is usually a casting, is stressedin compression, rather than in tension as in former clutches in whichthe driving memher was provided with internal scallops, and normallysubjected toexpansive forces which the member was required to resist intension. ;As will be understood, cast metal is not particularly strongin tension but is capable of withstanding relatively high compressivestresses. g 7

Still further, another feature of this invention isthe provision of newand improved means for securing the drivingground wheel to the drivingmember of the clutch, which does not weaken any of the clutch parts.

These and other objects and advantages of the present invention will beapparent to those skilled in the. art after a consideration of thefollowing detailed description, taken in conjunction with theaccompanying drawings illustrating the pre- 'ferred form in which theprinciples or the invention have been incorporated.

In the drawings:

' Figure 1 is an elevationalview ofa power lift clutch mechanismadaptedfor use on a tractor plow having a swinging crank axle, movementof which serves to raise and lower the plow bottoms;

Figure 2 is a view similar to Figure 1, but with certain parts brokenaway along the section line 7 22 of Figure 4, in order to'show theinternal construction and Figures 3 and 4 are side views, with thedriving ground wheel and one part of the casing removed,

showing the operation of the clutch mechanism V and controlling meanstherefor;

Figure 5 is a view taken generally along the line 55 of Figure'2,showing the manner of mounting the ground wheelfiin driving engagementon the driving member of the clutchyand Figure -6' is a section takenalong the 'line 6-5 of Figure .3, showing the clutch engaging roller andassociated parts. r v

Referring now to the drawings, more particu- V larly to'Figures 1 and 2,the reference numeral l 7 present arrangement of the clutch plow, suchas one of the type shown in my prior patents mentioned above. Thecrankaxle I extends downwardly and forwardly, and at its lower end isreceived in the socket portion 2 of a rear axle sleeve 3, the latterhaving a transverse shaft receiving bore 4 therein. The forwardmost endof thecrank axle I is threaded, as at 5,

and receives a nut 6 and a spring I by which the' sleeve 3 is fixed tothe crank'axle I so asto form, in effect, a part thereof. Journaled forrotation in the bore 4 of the sleeve 3 is atransverse land wheel axle I0carrying a crank II' at its inner end, suitably secured thereto as bywelding I2, and the outer end of the crank- II is apertured to receivethe lower outturned end I3 of a link I4 which extends generally upwardlyand is pivoted to a depth adjusting lever on the plow, as inconventional construction. The opposite or outer end of the axle I6receives a land wheel I! having a hub I8 by which the wheel II isfixedtoithe driving member I9 of a power lift "clutch mechanism indicated inits entirety by the reference numeral 26. The manner in which the wheelI1 is secured in place on the driving member I9 of the clutch 26 willbedescribed below. 7

The clutch 26 is of novel construction. Disposed about the stub shaft I0between the crankaxle. I and the wheel I1 is a clutch casing indicatedin its entirety by the reference numeral 2| and comprising two casingparts 22 and 23. The former preferably is formed integrally with thesleeve 3, but of course it may be formed separate ly and suitablysecured thereto in any suitable manner, if desired. The casing part 23is in the formof a bell housing and carries suitable sealing means 25which engages the hub portion 26 of the driving clutch member |9-. Thepart 23 also includes a flange which is bolted, as at 29, totheperipheralsection 30 of the other casing part 22. Thebolts 29 arepulled up tight so as to prevent leakage of lubricant at the joint between the two casing parts 22 and 23. The sleeve 3 and the casing 22, asbest shown in Figquently and their not a complete revolution at any onetime. V

The clutch-mechanism is completely enclosed within the casing 2|, exceptthat the shaft I0 as the driven part of the clutch and the member I9 asthe driving part extend laterally outwardly of the clutch casing 2| fromopposite sidesthereof.

these parts.

and the latter isprovided with a flange 44 which is provided withnotches or scallops 46 facin generally radially outwardly, as best shownin Figures 3 and 4. The hub portion 26 is provided with an enlarged bore4? which receives and is journaled for rotation on the hub 36 of thedriven member 34. The member I9 is formed with a shoulder 48 which isdisposed so as to bear against the outer end of the hub 36, there beinga thrust washer 49 serving as a bearing between A similar thrust washer5| is disposed between the laterally inner end of the hub section 36 andthe outer end of a flange 52 which forms a part of the sleeve 3 and thecasing part A pair of roller supporting straps 54 and 55 are pivoted bymeans of a pin 56 to an apertured boss 51 formed on or carried by themember 34. The" supporting straps 54 and 55 are generally arcuate, asbest shown in Figures 3 and 4, and at their opposite ends carry a casehardened roller 59 mounted for rotation on a pin 6| that is welded atits. opposite ends to the supporting straps 54 and 55. The straps 54 and55 and the roller 59, with. cooperating parts, constitute a clutch dogor clutch pawl for optionally connecting the driving and driven membersI9 and 34. As best shown in Figure 6, the roller 59 does not extend allthe way from one supporting strap to the other The clutch mechanism, asbest shown in Figures but, instead, has one end disposed closely adjacent the flange section 39 of the member 34.

However, the pin 6| extendsthrough a slot 63 formed in the flange 39 atan angle to a radius, as best shown in Figures 3 and 6. Also, the pin 6|extends entirely through the strap 54 that is disposed on the side ofthe member 34 opposite the roller 59 and the strap 55. The extended endof the pin BI is indicated by the reference numeral Sid and is receivedin a generally radially extending slot 65 formed in a latch plate or dog66 which is mounted for rocking movement on a reduced portion 6'!(Figure 2 of the hub 36 of the member 34. Thusthe latch dog 66 ismountedfor movement about the same axis about which the driving anddriven members I9 and 34 are movable. As best shownin Figures 3 and 4,

and 42 formed in the flange 39 of the member 34,

the radial slot 65,being formed in the arm portion II of the latch dog66, as shown in Figure 6. Due to the relation between the slots 63 and65, the former being disposed at an angle to the length of the slot 65,which is disposed generally radially, whenever the member 65 is rockedin one direction or the other relative to the member 34, the rollersupporting straps 54 and and the roller 39 carried thereby is swungtoward or away from the scallops or notches 46 formed in the externalperipheral portion of the clutch driving member I9. From Figures 3 and4, it will be seen that the slot 63 in the member 34 is disposedgenerally radially about the pivot 56 by whichthe roller supportingstraps 54 and 55 are connected to the driven member 34. One of thestraps, as the strap 55, is extended, as at 55a (Figures 3 and 4), andis apertured to receive one end of a spring I5, the other end of whichis anchored, as by a pin I6 to a lug 'I'! that is formed on the drivenclutch member 34. The spring 15 therefore normally biases the rollersupporting member 54, 55 for movement in a direction to carry the roller59 into engagement with any one of the notches or scallops 46, and whenthe roller 5. is disposed inone of the notches 46, the arms 7 H and I2of the latch dog 66 occupy positions overlying, at least partly, theassociated notches ll and 42 inthe member 34.

The casing 20 is extended, as at 20a (Figures 3 and 4;), and is providedwith apertured bosses 8| and 82 (Figure 2), in which a pin 83 ismountedfor rocking movement. A trip lever 84 is fixed in any suitable way, asby a nut 85, to the outer end of the pin 83, and to the latter inside.thecasing 20 a pair of arms 86 and 81 are fixed, as by welding or thelike. The arms 86 and-8! are disposed in spaced apart relation and attheir outer ends support a-roller 88 mounted on a pin 09 which iscarried by the outer ends of the arms 86 and 81. The arm 86 carries alug 9I (Figure 4) to' which oneend of a spring 92 is -connected, the;

other end of the spring being connected to a nut member 93 into which isthreaded an adjusting bolt94. The casing 30is provided with a boss 95receiving the adjusting bolt 94.' As best shown in Figure 4, thespring'92 is arranged so as to .urge the trip roller 88 into ,a positionin one or the other of the notches II and 42, the roller 88 at'othertimes bearing against the peripheral surface or edge of the drivenclutch member 34,

From Figure 2 it will be noted that the relatively long bearingwhich'the sleeve 3 has on the axle I serves to hold the latter againstdisplacement and that the axle I0 therefore serves to support the clutchandother parts, including the 1 driving clutch member I9 which ismounted for rotation about the axle I0 and on the hub sec-.

tion 36 of the driven clutch member 34. The land wheel I1 is mounted onthe laterally outwardly extended portion of the member I9 and the mannerof connecting the wheel IT to the member I9 will now be described.

The laterally outwardly extended portion of the member I9 is indicatedby the reference nu-' meral I9a in Figures 2 and 5, and this extendedsection is provided with a plurality, preferably three, axiallyextending circumferentially spaced ribs H3, each rib'being lower 'in itscentral porhub receiving sections H311. and II3b. 'The extended sectionI9a of the member I9, and the ribs II3 as well, taper generally axiallyoutwardly, and the interior of the wheel hub I8 is of opening 99 soas toreceive the ribs I I3 on the membenl9. As best shown in Figure 2, theribs 7.

H3 terminate, short of the hub section 26 where- .by there is a space 8into which the ringmem- T ber 91 may be moved and be free of the ribs II3 so that the ring member may then be turned angularly about the axisof the clutch, thereby interlockirig, in efi'ect, the member 91 with themember I9. The ringsmember 91 is also provided with a plurality of boltholes IOI which are adapted to receive. bolts I02 which extend outwardlythrough openings I03 in the hub I8 of the wheel I1," as best shown inFigure 2. At the outer end of the wheel I! a cap I03 having an aperturedflange I04 is disposed over the threaded outer ends of the bolts I02.Preferably, sealing means I is disposed adjacent the inner end of thecapI03 and engageable with the member I9 whereby anylubricant leakinglaterally outwardly along the axle I0. will be confined about the outerend of the members I0 and I9.

By drawing up on the bolts I 02 the wheel I! will, be clamped on thetapered portions of the driving clutch member I9. Also, the bolt holes IM in the ring member 91 and the bolt holes I03 in the hub I8 of thewheel I! are so arranged that when the ring member 91 is engaged orinterlocked with the inner endsof the ribs I I3, the

wheel IIis in aposition in which the ribs I I5 on tion, therebyproviding twoaxially spaced wheel collar I08 to adiiferent position,wear in the complementary formation. Further, the hub I8 of the wheelisprovided with a corresponding number of radially inwardly axiallyextending ribs I I5 drawing the wheel axially into clamping engagementwith the driving clutch member I9. Such means will now be described.

According to the present invention, means is provided fordrawing thewheel I'I into. place on the member I9, but such means is arranged sothat it may be applied ontothe member I9 from c the same end thereofthat receives the wheel I'I,

whereby it is not necessary to' dismantle the clutch or other parts whenattaching or removing the land wheel H. A ring 91 having an' axiallyinwardly directed flange 98 serving as a dust collar surrounding theouter end of the clutch casing 20, is'provided with a-central opening 99adapted to pass over the outer end of the member I9, and the opening 99isfurther provided with notches I00 opening into the central the insideof the hub I8 thereof-are disposed against one side of the associatedribs II3 on the member I9. As will be readily understood,

the parts are arranged so that the ribs or lugs H3 and H5 engage oneanother in the driving direction, as indicated by the arrow in Figure 5.

The thrust or wearing washers 49 and 5| are preferably hardened steel.If end play develops in the clutch parts, such play may be taken up 'byadjusting means at the outer end of the axle I0. An opening I06 isformed in the outer end of the axle I0 to receive a pin III'I. Anadjusting collar I08 is fitted over the outer end of the axle I0 andbears against the outer end of the member I9 througha wearing washerI09. Theicollar I08 has a plurality of stepped castellations III ofdifferent axial dimensions, whereby by removing the. pin I 01 andturning the take-up washers 48 and 5| may be accommodated. When the wearin these partsbecomes accessive, they 7 may, of course, be replaced.

The operation of the clutch described above is substantially as follows.a

Figure 3 represents the parts as they are arranged when the plow bottomsare raised and a pull'has' been exerted by the operator, usually througha cable or the like, on the trip lever 84 position, relative tq themember 34, that is shown rocking the same and the trip-arms 81 in acounterclockwise direction as viewed in Figure 3. It will be rememberedthat the driving'member I9 of the clutch normally rotates in acounterclock-i wise direction as viewed in Figures 3 and 4. Norlmally,'when the clutch mechanism is inactive, the

spring 92 holds the roller 88 in one of the notches 4| and-42, whichforces the latch dog. 66'into a in Figure 4'and which holds the roller59 out-of the path of movement of the scallops or notches 46 on thecontinuously rotating member I9.

However, when the operator exerts a pull on the I trip lever 84,swinging the same in a counterclockwise direction as viewed-in Figures 3and 4,

the roller 88 is moved out of the notch42 (Figure 3), which permitsthespring ,15 to pull the roller 59 into the path of movement ofthe notches46,

l0, thereby insuring that the, clutch remain en- V latch dog B6,.thearm12 of which bears against the roller 88 during this retracting movementof the latter, as shown in Figure 3. When the roller 88 is completelydisengaged from the notch 42 (Figure 3) the spring 75 pulls the roller59 into one of the scallops or notches 46.. The latter are formed sothat when the roller 59 seats in one of the notches driving connectionis established between the continuously rotatable member l9 and thedriven member 34 of the clutch. From. Figure 3, which illustrates theparts as they move into driving connection, it will be seen that theroller supporting straps 54 and 55 extend across the member I!) so thata line connecting the pivot 56 with the roller pivot 6| is disposed inchordal relation with the flange 44 in which the notches 46 are formed.The straps 54 and 55 are curved gaged Whenever the movement of the latchlever 66 has permitted the roller 59 to enter one of the notches 41.However, the release of. the clutch is readily effected by releasing thetrip lever 84, as described above.

While I have shown and described above the preferred structure in whichthe principles of ,the present invention have been incorporated, it isto be understood that my invention is not, to be limited totheparticular details shown anddescribed above, but that, in fact, widelydifferent a .means maybe employed in the practice of the so as toclearthe hub portions26 of the member l9; otherwise such member could bestraight. The members 54 and 55 thus act in tension to transmit thedriving force from the member I!) to the member 34. Heretofore, in priorclutches, the parts were reversed so that the'roller sup porting strapswere required to transmit driving forces in compression or with apushing action. As will be obvious, such members are much stronger intension than they are in compression since in the latter case they haveto be sufficiently rigid to resist buckling. Further, the drivingstresses which are transmitted from one clutch member tothe other areapplied to'the member IS in compression, rather than in tension, as isthecase where the notches or scallops are formed construction.

The clutch of the present invention remains engaged, with the strapmembers 54.and 55 transmitting the drivingforce in tension with themember l9 stressed largely in compression, so longas the operator holdsthe trip lever 84 in a position with the roller 88 out of contact with Ithe notches 4| and 42. However, in normal operation, as soon as theclutch begin to drive the parts the operator releases his hold on thetrip lever cable, whereupon the spring 92 swings the trip arms 86 and8'! in a clockwise direction (Figure 3) causing the roller 88 to ridealong the periphery of the member 34 'until it reaches the notch 4|. Asoon as this occurs the spring 92 starts to move the roller 88 into thenotch 4|, but since the arm H of the latch dog. 66 is heldagainstfurther rotation by engagement with the roller 88, the relativemovement that occurs as a result thereof between the member 66 and thedriven clutch member causes the slots 63 and 65 to swing the rollersupporting straps 54 and 55 outwardly carrying the roller 59 out ofengagement with the notch in the member [9, thereby disconnecting theclutch. The relation of the pivots 56 and 5! when the roller 59 isseated in one of the notche 45, with respect to the axis of the parts113, l9 and 34 is such that when the member I9 is rotated in thedirection of the arrow the effect is to cause the strap members54 and 55to syving inwardly toward the axis of the shaft member, and a connectingmember pivoted at one broader aspects of my invention.

What I claim, therefore, and desire to secure by Letters Patent is:

1.' A self-interrupting clutch comprising a rotatable drivin member inthe form of a casting having a flange the peripheral edge of which has aplurality of external notches, a driven member mounted coaxially of andadjacent the driving end to said driven member at a point adjacent theexternal notches of said'driving member and having means at the otherend movable into engagement with one of the notches on said drivingmember, said connecting member extending from its point pf pivotalconnection with said driven member generally in the direction ofrotation of I the latter and generally in chordal relation with respectto the notched periphery of the driven member, whereby the transmissionof the drive to the driven member from the notched driving memberstresses the latter in compression and said connecting member intension.

2. A self-interrupting clutch comprising a rotatable driving memberhaving a hub and a, peripheral section provided with a plurality ofgenerally radially outwardly facing notches, a driven member having aradially extending part and a hub, a connecting member pivoted at oneend to said radially extending part of said driven member adjacent thenotched periphery of said driving member and having means at its otherend movable into engagement with one of thenotches on said drivingmember, said connecting member, when said means lies in one of saidnotches, lying alongside and generally radially inwardly of the adjacentperiphery of said driven member, said connecting member extending fromits point of pivotal connection with said driven member generally in thedirection'rof rotation of the latter,

whereby the transmission of the drive to theposed radially outwardly ofthe surface of said outer endportion, a wheel, and detachable meansfor'connecting said wheel to the outer end portion of said one member atpoints thereon generally radially inwardly of the outer surface of theportion of said one member which receives said casing part. a

4. In an agricultural machine, the combination of driving and drivenmembers, a clutch casing enclosing said members and including a parthaving sealing means which is adapted to be passed over one of saidmembers and engaged with, a portion of the latter in sealing relation,wheel receiving means on said one member extending in a radial directiona distance not greater than the portion of said one member receivingsaid sealing means, a wheel, and means for attaching said wheel to saidwheel receiving means.

Clutch mechanism comprising a driven member including a hub and a flangemovable therewith, a driving member journaled for rotation on saiddriven member and also including, a hub and a flange, the flanges ofsaid members being disposed adjacent one another, the external peeripheral section of one of said flanges being provided with a pluralityof notches, connecting means movably mounted on the other flange ad--jacent the path of movementof said notches and adapted to be moved intoa position to engage said notches'whereby to connect said driving anddriven members together with said connecting -of said members inlubricant tight engagement,

and means on the interior of said casing for controlling the position ofsaid connecting means. I 6. Clutch mechanism comprising meansservanddisposed on oppositesid thereof, said one ,member having a slottherein arcuate with re spect to the pivot of said straps, a'pinextending'through said slot and connected to the other ends ofsaid'straps, means on said straps engageable with the other ofsaiddriving and driven members, and a plate'pivoted for'movement' aboutan axis on said one member and having a slot receiving said pin, saidslot being so disposed that rocking movement of said plate swings saidmeans into and out of engagement with said other member.

10. Clutch mechanism comprisinga pair of driving and driven members,oneof said members having external teeth, a pair of straps pivoted tothe other of said driving and driven mema teeth of said one member forestablishing a driving as a casing, a constantly rotatable drivingmember extendinginto said casing means, a driven member disposed withinand including a part extending out of said casing means in coaxialrelation, a clutch dog within said casing pivotally connected with onemember and engageable with the other member for optionally connectingsaid members in driving relation, means serving as a latch dog pivotedfor movement about the axis of said driving and driven members, and aconnection between said latchdog means and said clutch dog wherebymovement of the latter is efiected by movement of the latch dog meansabout the axis of said driving and driven members for controlling saidpivoted clutch dog.

7. In an agricultural implement, a lifting clutch of theself-interrupting type adapted to raise tool means or the like intoaraised position,,said

clutch mechanism comprising driving and driven parts mounted incoaxialrelation, a clutch pawl pivotally mounted on one of said partsand engageable with the other for connecting said parts together indriving relation, a member mounted for rocking movement about the axisof said parts,

said member being operatively connected with 8. Clutch mechanismcomprising a constantly rotatable driving member, a, driven member, a

clutch dog pivotally connected with one member and engageable with theother member for optionally connecting said members in driving relation,means serving as a latch dog, pivoted for movement about the axis ofsaid driving and driven' members for controlling said pivoted clutchdog, said latch dog means including two outwardly extending arms, andmeans engageable with said arms for controlling said clutch mechanism. ii

9. Clutch mechanism comprising a constantly rotatable driving member, adriven member, a

ing connection between driving and driven members, and a latch platepivoted for movement about the axis ojf said driving and driven'membersand having a slotreceiving said pin, said slot beingsodisposedthatrocking movement of the other end of said part, means onsaid part engageable with the other of said driving and driven members,and a second part pivoted for movement about an axis on said one memberand having a slot receiving said pin, said last mentioned slot being sodisposed that rocking movementof said plate-swings said means 'into andout of engagement with said other member.

1 2. Clutch mechanism comprising a pair of driving and driven membersoneof said members having externalteeth, a part pivoted adjacent one end tothe other of said driving and driven members, said other member having aslot therein arcuate with respect to the pivot of said part, a pinextending-through said slot and connected to the other end of said part,a roller disposed on said pin and engageable with the teeth of said onemember for establishing a-driving connection between driving and drivenmembers, and

e a latch plate pivoted on said'driven-member and pair of straps pivotedto one of said members having a slot receivingsaid pin, said slot beingso disposed that rocking movement of said plate swings said roller intoand out of engagement with the external teeth on said one member.

13. Self-interrupting clutch mechanism com- I prising flanged coaxiallymounteddrivingand driven members, the flanges of said members bei-ngdisposed adjacent one another, the external peripheral section of one'ofsaid;fiangesbeing provided with a plurality of notches, connecting meansmovably mountedon the other flange admeans normally urging saidconnecting means into a position connecting said driving and drivenmembers, and means 'for controlling the position of said connectingmeans.

14. Self-interrupting clutch mechanism comprisingcoaxially mounteddriving and driven members, a clutch dog pivotally connected with onemember and engageable with the other member for optionally connectingsaid members in driving relation, means serving as a latch dog adjacentsaid members in a position to engage the ends or said latch dog meansoptionally.

CARL G. STRANDLUND.

